FR3075868B1 - DEGASSING TUBE FOR A REDUCING AIRCRAFT TURBOMACHINE - Google Patents

Abstract

Degassing tube (20) for a geared-up aircraft turbomachine, the degassing tube having an elongate shape and being adapted to extend at least partly along and inside a turbine shaft (4) of the turbomachine, characterized in that it comprises at least one upstream section (20a) comprising on the one hand peripheral means (28) for securing in rotation with an input shaft (8) of a gearbox (7) and first peripheral sealing means (26) configured to cooperate with said input shaft.

Description

Degassing tube for a reducer aircraft turbine engine

TECHNICAL AREA

The present invention relates in particular to a degassing tube for an aircraft turbomachine, in particular with a reduction gear, for example an epicyclic or planetary gearbox.

STATE OF THE ART

A turbomachine, such as a turbofan engine, conventionally comprises an air intake comprising a fan whose outlet air flow is divided into a flow of air which enters the engine and forms a hot flow or flow primary, and a flow of air flowing around the engine and forming a cold flow or secondary flow.

The engine typically comprises, from upstream to downstream, in the direction of flow of the gases, at least one compressor, a combustion chamber, at least one turbine, and an exhaust nozzle in which the combustion gases exit the turbine. and forming the primary stream are mixed with the secondary stream.

At its downstream end, the turbomachine comprises an ejection cone of the primary flow or of the primary flow-secondary flow mixture. This cone has an elongate shape, the upstream end of larger diameter is attached to an element of the turbomachine, such as a housing.

A de-oiler is used in the engines to recover the oil and thus limit oil losses. This saving in oil makes it possible to have a tank of oil embedded as small as possible for gains of mass. On the other hand, the de-oiler is integral in rotation with a shaft of the turbomachine and is very dependent on the speed of rotation of this shaft and the radius on which the de-oiler is installed. There are two types of de-oiler: the free vortex and the forced vortex. There is talk of free vortex when there is relatively little obstacle in the path of air through the de-oiler, and forced vortex when there are several obstacles. The free vortex takes up more space and requires only one cavity. The forced vortex takes up less space but requires obstacles such as radial pipes, a grid, etc. For a geared motor with a low blower speed, a free vortex de-oiler may not be sufficient.

In a conventional manner, a degassing tube passes longitudinally through the turbomachine to the ejection cone. This tube has the function of channeling the oil discharged air by de-oilers of the turbomachine to the ejection cone located downstream.

Documents FR-A1-2 957 973, FR-A1-2 957 974 and FR-A1-2 993 311 describe turbomachine degassing tubes.

A degassing tube has an elongate shape and is adapted to extend at least partly along and within a turbine shaft of the turbomachine. The degassing tube is intended to receive deoiled air from the lubrication chambers of the turbomachine. Thus the lubrication chambers are ventilated and connected to the atmosphere, which allows the extraction of deoiled air.

In the case of a turbofan engine, the turbine shaft drives the fan shaft through the gearbox which is lubricated and housed in the upstream lubrication chamber. Depending on the type of gearbox used, planetary or epicyclic, the fan shaft will rotate in the same direction or in the opposite direction to the turbine shaft, and the fan shaft will rotate at a lower speed than that of the turbine shaft.

The enclosure is delimited by fixed walls (housings) and movable (shafts of the turbomachine). At the interface of moving walls relative to each other, sealing means are provided to control oil leaks. The document WO-A1-2015 / 075355 describes, for example, labyrinth-type peripheral sealing means provided between the fan shaft and the input shaft of the gearbox.

However, there is a need to ensure a seal between the degassing tube and the surrounding elements, in particular in a geared turbine engine, regardless of the type of this reducer.

There is also a need to ensure optimum filtration of the oil-laden air leaving the lubrication chamber, to ensure that a maximum of oil is separated from the air intended to flow into the degassing tube. The separated oil is intended to be collected and rerouted to the lubricating oil circuit.

The present invention provides an improvement to the current technology of degassing tubes, and allows to meet at least one of the above needs.

SUMMARY OF THE INVENTION

The invention proposes a degassing tube for a geared-up aircraft turbine engine, the degassing tube having an elongated shape and being intended to extend at least partly along and inside a turbine shaft of the turbomachine, characterized in that it comprises at least one upstream section comprising on the one hand peripheral means for securing in rotation with an input shaft of a gearbox and first peripheral sealing means configured to cooperate with said input shaft.

The upstream section of the degassing tube is thus intended to be secured in rotation with the input shaft of the gearbox, and to cooperate sealingly with the fan shaft. The invention thus proposes to ensure a seal between the degassing tube and the fan shaft, which can be added to the aforementioned seal between the fan shaft and the input shaft of the gearbox. The upstream section of the tube and the input shaft of the gearbox will thus rotate at the same speed, which is that of the turbine shaft to which the input shaft of the gearbox is connected. The fan shaft will rotate at a lower speed and in an identical (co-rotating) or different (counter-rotating) direction from that of the degassing tube, the additional sealing means ensuring a seal between these two rotating elements. whatever their configuration (co-rotating or counter-rotating).

The present invention also provides a degassing tube for an aircraft turbomachine, the degassing tube having an elongate shape and being adapted to extend at least partly along and inside a turbine shaft of the turbomachine, characterized in that it comprises at least one upstream section in which is mounted coaxially a filter cartridge, said filter cartridge comprising a pierced annular envelope and surrounding a filter configured to separate the oil from a flow of gas intended to pass through axially said section.

This degassing tube is thus equipped with a filter cartridge for separating the oil from the air flow of gas exiting for example a lubrication chamber of a gearbox of the turbomachine. The tube is generally integral in rotation with a rotor element and the oil of the gas flow which flows axially through the section will be centrifuged and recovered in the filter, with a view to its reinjection into the lubrication.

The tube according to the invention may comprise one or more of the following characteristics, taken separately from each other or in combination with each other:

the tube further comprises second peripheral sealing means configured to cooperate with a fan shaft intended to be driven by said gear,

the fan shaft is rotatable relative to the degassing tube,

said first and second sealing means are chosen from O-ring or labyrinth seals,

said upstream section comprises a downstream end configured to be axially engaged in an upstream end of an intermediate section,

said downstream end comprises axial locking and / or sealing means configured to cooperate with said intermediate section,

said upstream section comprises at least two, and preferably at least three, portions of different diameters,

said upstream section comprises an upstream portion of larger diameter, an intermediate portion of intermediate diameter and a downstream portion of smaller diameter, the upstream and intermediate portions being interconnected by a first frustoconical wall and the intermediate and downstream portions being connected. between them by a second frustoconical wall,

said second sealing means are situated on the upstream portion, and said first sealing and securing means are located on said intermediate portion,

a filter cartridge is mounted coaxially inside said upstream and intermediate portions, and for example fixed by an upstream end to said upstream portion,

said upstream section comprises at an upstream end hooks for gripping the tube with a view to its assembly / disassembly by axial translation,

the intermediate section comprises, for example at an upstream end, fastening means to said turbine shaft and third peripheral sealing means configured to cooperate with this turbine shaft,

said third sealing means are contact sealing means,

the tube comprises at least one downstream section comprising, for example at a downstream end, fastening means to said turbine shaft and fourth peripheral sealing means configured to cooperate with this turbine shaft or a tubular element intended to extend in the axial extension of the turbine shaft,

said cartridge comprises an upstream end surrounded by said upstream portion and fixed to this upstream portion,

said cartridge comprises at its upstream end an annular flange for attachment to said upstream portion, this flange comprising an annular row of oil passage orifices,

said casing has a generally cylindrical shape and is open at its upstream end and closed at its downstream end,

said envelope is separated from said section by an annular space,

said openings open into said space,

- Said intermediate portion has a slightly frustoconical general shape flared upstream so that the oil filtered and recovered by centrifugation on this section can flow to said holes of the cartridge.

The invention also relates to an aircraft turbomachine, for example a reducer, characterized in that it comprises a tube as described above. In the case of a turbomachine with a reduction unit, the turbomachine comprises at least one turbine shaft whose upstream end is fixed to an input shaft of a gearbox, and a fan whose shaft is fixed to an output shaft of the gearbox, fifth sealing means being mounted between the input shaft of the gearbox and the fan shaft or the output shaft of the gearbox.

The turbomachine according to the invention may comprise one or more of the following characteristics, taken separately from each other or in combination with each other:

said fan shaft and said tube are configured to rotate in the same direction,

said fan shaft and said tube are configured to rotate in opposite directions,

said second peripheral sealing means are located between an annular pressurization cavity and a cavity of a deoiling system, and said fifth peripheral sealing means are situated between said annular pressurization cavity and a lubrication chamber,

said pressurization cavity is in fluid communication through air calibration orifices passing through an outer annular ring of support of said first peripheral sealing means, with another annular cavity extending around said upstream section,

said other pressurization cavity is configured to be supplied with compressed air taken from a compressor of the turbomachine,

said de-oiling cavity communicates with said lubrication chamber by an annular row of deoiling tubes which pass radially through said fan shaft,

said lubrication chamber encloses said gear and bearings,

said lubrication chamber is delimited by labyrinth sealing means which are configured to be traversed by operating ventilation air flows.

DESCRIPTION OF THE FIGURES

The invention will be better understood and other details, characteristics and advantages of the invention will appear on reading the following description given by way of nonlimiting example and with reference to the appended drawings in which:

FIG. 1 is a diagrammatic view in axial section of a turbomachine with an aircraft reducer,

FIG. 2 is a diagrammatic view on a larger scale of part of FIG. 1,

FIG. 3 is another partial schematic view of the turbomachine of FIG. 1, and shows a degassing tube according to the invention,

FIG. 4 is a schematic half-view in axial section of an upstream section of the degassing tube of FIG. 3,

FIG. 5 is a schematic perspective view of the upstream section of the degassing tube of FIG. 3, and FIG. 5a is a view on a larger scale of a detail of FIG. 5,

FIG. 6 is a schematic half-view in axial section of an intermediate section of the degassing tube of FIG. 3;

FIGS. 7a and 7b are diagrammatic perspective views of the axial ends of the sections of the tube of FIG. 3,

FIG. 8 is a schematic half-view in axial section of a downstream section of the degassing tube of FIG. 3, and

FIG. 9 is a schematic perspective view of an axial end of a downstream section of the tube of FIG. 3.

DETAILED DESCRIPTION

Referring to FIG. 1, there is shown a turbomachine 1 with a gearbox, which comprises, in a conventional manner, a fan S, a low-pressure compressor 1a, a high-pressure compressor 1b, a combustion chamber 1c, a high-pressure turbine 1d and a low pressure turbine 1e. The rotors of the high pressure compressor 1b and the high pressure turbine 1d are connected by a high pressure shaft 5 and form with it a high pressure body (HP). The rotors of the low pressure compressor 1a and the low pressure turbine 1e are connected by a low pressure shaft 4 and form with it a low pressure body (BP). The fan is, in turn, carried by a fan shaft 3 which is connected by a gear 7 to the LP shaft 4.

HP and BP trees extend along an axis which is the axis of rotation of the turbomachine 1. In the following description, the concepts of longitudinal or radial, and indoor or outdoor, are related to this axis.

The turbomachine 1 comprises structural housings. The HP body is held by two structural housings: the inter-compressor housing and the inter-turbine housing, and the LP body is held by at least two structural housings: the intermediate housing 2 and the inter-turbine housing and / or the housing exhaust 6.

The intermediate casing 2 supports bearings of the LP turbine shaft 4 which are housed in a front or upstream enclosure denoted E1. The exhaust casing 6 supports bearings of the LP turbine shaft 4 which are housed in a rear or downstream enclosure denoted E2.

The enclosures are generally partially delimited by bearing supports.

The reducer 7 is here epicyclic type. Figure 2 shows very schematically the size of the gearbox. The gearbox 7 comprises an input shaft 8 extending upstream of the LP shaft 4 and which is guided by a downstream bearing bearing 10 of this BP shaft. The output torque of this gear 7 is transmitted to the fan shaft 3, by a conventional connection, known to those skilled in the art, such as for example an attachment of this fan shaft to the carrier forming a planet shaft. output 9 of the gearbox, in the case of an epicyclic reduction gear. In the case of a planetary gearbox, the fan shaft would be driven by the crown. The reducer is placed inside the front chamber E1 lubrication.

The enclosure E1 comprises fixed walls and movable walls. The fixed walls of the enclosure E1 comprise an internal wall of the vein of the primary flow, an upstream bearing support 11 and a downstream bearing support.

12. The supports 11 and 12 extend inwardly of the turbomachine and bear respectively the bearings 13, 14 and the bearing 10. They provide the structure between the casings and the fixed outer rings of the bearings. The movable walls of the enclosure E1 comprise the input and output shafts 9. The bearings 10, 13, 14 are housed in the enclosure E1. Seals 17a, 17b are provided between the fixed and movable walls and are, for example, labyrinth seals, brush seals, segmented radial seals, etc.

The bearings 10, 13 and 14 and the gear 7 are lubricated for their proper operation. The oil is supplied by appropriate means (arrows 16) such as nozzles, oil feed pipes, etc. The bearings 10, 14 are located at the axial ends of the enclosure E1. The bearing support 13 comprises ventilation holes that allow ventilation air to pass through the enclosure. The enclosure E1 is configured so that the air-oil mixture, which forms an oil mist inside the chamber, is contained in the latter. Between the rotor and stator walls of the enclosure, for example here at the upstream and downstream ends of the enclosure, seals 17a, 17b are placed to contain the oil, and an air circuit pressurizes these seals to avoid oil leaks (arrows 17). The enclosure E1 is then pressurized (air enters continuously, pushing the oil that could have come out of the seals by capillarity) and the bearings operate in a medium of oil and air mixed. The bearings are fed by an oil feed tube 16 and the oil recovery by a specific recovery tube. To avoid an overpressure of the enclosure, and allow a constant flow of incoming air, the interior of the enclosure is vented at a lower pressure than the pressure of the air entering the seals. This air loaded with oil particles, which is discharged at this pressure well, must first be treated to recover almost all the oil it conveys. For that, the oiled air will be brought to an oil separator which will separate the air of the oil that it conveys and will reject the deoiled air outside the engine. This is the de-oiling principle of an enclosure.

The enclosure is vented by a degassing tube 20 which passes axially through the LP turbine shaft 4, from the upstream chamber E1 to the ejection cone 6b of the turbomachine.

The de-oiler generally comprises an annular row of deoiling tubes 21 which pass radially through the fan shaft 3 and allow the passage of oiled air radially from the outside towards the inside, from the enclosure E 1 to a cavity R arranged upstream of the degassing tube 20 (arrow 18). Under free vortex effect, the speed of rotation of the oiled air increases rapidly while approaching the motor axis and the oil is centrifuged on the internal walls of the fan shaft 3 to return to the enclosure E1 (arrows 19).

One of the aims of the invention is to arrange a degassing tube in a particular gear type motor to allow de-oiling of the enclosure E1. The tube must here be arranged to perform its de-oiling function by being suspended both by the LP turbine shaft and the fan shaft, these two shafts being co-rotating or counter-rotating.

In the example shown, the HP body is counter-rotating with the fast BP body. But the HP body can very well be co-rotated with the fast BP body and it does not change anything depending on the type of reducer.

FIG. 3 illustrates an embodiment of a degassing tube 20 according to the invention.

The degassing tube 20 is made in several sections in the example shown in FIG. 3 and following. It comprises an upstream section 20a, an intermediate section 20b and a downstream section 20c. The sections are coaxial and extend one behind the other, their opposite axial ends being nested one inside the other.

The upstream section 20a is better visible in FIGS. 4 and 5. It is configured to be secured to the LP turbine shaft and comprises independent sealing means intended to cooperate respectively with the fan shaft 3 and with the shaft input 8 of the gearbox 7.

The upstream section 20a thus provides a double rotor / rotor seal with a first seal with the input shaft 8 of the gearbox and a second seal with the fan shaft 3. The rotational speed of the input shaft 8 the gearbox is greater than that of the fan shaft 3. The difference in rotational speeds between these rotors depends on the reduction ratio of the gear 7 that is planetary or epicyclic. The number of supports of the tube 20 with respect to surrounding elements and the materials are chosen to avoid vibrations of the constituent elements of the tube in the operating range of the engine.

In the example shown, the upstream section 20a comprises three axial portions, respectively upstream 20aa, intermediate 20ab and downstream 20ac, of different diameters. The upstream portion 20aa has the largest diameter and has a generally cylindrical shape. It carries at its outer peripheral sealing means 22, here of the labyrinth type (such as radially external annular wipers), intended to cooperate with means complementary to the fan shaft 3. This upstream portion 20aa comprises at its free end end an annular row of hooks 24 for forming an extraction means during assembly and disassembly of the section 20a of the turbomachine, by axial translation from upstream. The downstream end of the upstream portion 20aa is connected by a frustoconical wall 25 flared upstream to the intermediate portion 20ab, which has a median diameter. This intermediate portion 20ab is advantageously slightly frustoconical flared upstream to guide upstream oil which is deposited by centrifugation on the radially inner surface of this portion. The intermediate portion 20ab carries at its outer peripheral sealing means 26 and means 28 for securing in rotation to cooperate both with the input shaft 8 of the gearbox 7. These means 26, 28 are carried by an outer annular ring 29 formed in one piece with the section 20a. The ring 29 comprises an annular groove opening radially outwards and receiving an O-ring forming the sealing means 26. The ring further comprises an annular row of substantially radial claw teeth axially engaged in an annular row of complementary teeth of the input shaft 8, to form the securing means 28. The ring 29 comprises an annular row of axial orifices 32 passing through the air calibration to allow the passage of air around the section 20a, between the latter and input shafts 8 and blower 3 (arrow 33). This air is added to the air of the arrows 17 in order to pressurize the seals and prevent oil leaks. The ring 29 is here substantially located in a radial plane passing substantially through the sealing means 31, here labyrinth, between the input shaft 8 and the fan shaft 3.

The downstream end of this intermediate portion 20ab is connected by a frustoconical wall flared upstream to the downstream portion 20ac, which has the smallest diameter. The downstream end of this downstream portion 20ac is engaged axially in the upstream end of the intermediate section 20b and comprises at its periphery means 27 for axially locking the sections 20a, 20b which comprise a rod housed in grooves opposite the nested ends sections.

The frustoconical shapes opening upstream, in particular of the portion 20aa, serve to bring the oil upstream of the tube 20 to reinject it into the enclosure or into the main oil circuit. The radial offset between the portions 20aa and 20ab makes it possible to integrate the sealing means 31 and the orifices 32. The radial offset between the portions 20ab and 20ac makes it possible to prevent the oil having beaded on the portion 20ab from being driven downstream of the engine by the air flow.

A filter cartridge 30 is mounted coaxially inside the upstream section 20a, and more exactly inside the upstream portions 20aa and 20ab intermediate in the example shown (Figures 4 and 5). This cartridge 20 is generally necessary in case of low LP shaft rotation speed and / or low free vortex degassing radius.

A certain filter cartridge diameter is required to have a high peripheral velocity and promote air-oil separation. The diameter of the tube 20 is limited to limit the diameter of the LP shaft. The portion 20ab may be straight or slightly flared to further promote the return of the oil.

The cartridge 30 comprises an outer envelope 30a, here substantially cylindrical, which is pierced with substantially radial non-visible orifices and which surrounds a substantially cylindrical filter 30b. The envelope 30 comprises an intermediate cylindrical wall whose upstream end is connected to a radial flange 34 for attachment to the upstream portion 20aa of the upstream section 20a. This attachment may be a simple radial support of the flange, or a hooping, inside the upstream portion 20aa. The flange 34 comprises at its outer periphery, that is to say in the vicinity of the portion 20aa, an annular row of axial through-holes 36 of oil passage (Figure 5a). The upstream end of the envelope 30a and the cartridge 30 is thus open to receive de-oiled air from the enclosure E1. The downstream end of the envelope 30 is closed, for example a domed dome 30c downstream. This closure makes it possible to force all the oiled air to pass into the cartridge and promotes the separation air oil.

The envelope 30 is surrounded by the intermediate portion 20ab and separated by a small radial clearance of this portion so as to form an annular space 38 between the cartridge and the section 20a. This space 38 extends over the entire longitudinal dimension of the cartridge 30 and opens, downstream of the cartridge, inside the section 20a and is in fluid communication, upstream of the cartridge, with the cavity R via the orifices 36.

The intermediate section 20b is configured to be secured to the LP turbine shaft 4 and also comprises sealing means 40 intended to cooperate with the LP turbine shaft (Figures 4, 6 and 7a). The section 20b comprises at its upstream end an annular groove opening radially outwards and in which is housed an O-ring forming the sealing means 40. The upstream end of the section 20a further comprises means 42 for securing in rotation as well as in translation intended to cooperate with the LP turbine shaft 4. These means 42 here comprise a radially outer annular flange whose outer periphery is crenellated and defines clutch teeth axially engaged in a toothing of shape complementary to a upstream end of the LP turbine shaft. A nut 44 and a locking ring 46 may be mounted on this end of the LP turbine shaft to complete the assembly and prevent unintentional disassembly of the sections 20a, 20b.

The downstream end of the section 20b is engaged axially in the upstream end of the section 20c and comprises at its periphery sealing means 50 intended to cooperate with this section 20c (FIGS. 6 and 7b). These sealing means 50 are here formed by an O-ring housed in an annular groove opening radially outwardly of the downstream end of the section 20b.

Finally, the downstream section 20c is configured to be secured to the LP turbine shaft and also comprises sealing means 52 intended to cooperate with the LP turbine shaft or a tubular element 53 mounted in the downstream axial extension thereof. tree (Figures 8 and 9). The sealing means 52 are here of the labyrinth type and comprise external annular wipers formed projecting on the downstream end of the section 20c.

The downstream section 20c can be mounted from the rear of the engine. The downstream section 20c, according to its length, may comprise one or more radial support means on the inner surface of the LP turbine shaft 4. These bearing means comprise external annular flanges 54 extending radially towards the outside from the section 20c and supported by their periphery, possibly by a seal or damper, on the inner surface of the LP turbine shaft 4.

The downstream section 20c is fixed by its downstream end to the LP turbine shaft 4. In the example shown, it carries at its downstream end a tubular wall 56 which extends inside the LP turbine shaft. 4, at a short radial distance therefrom. This wall 56 comprises means 58 for securing in rotation as well as in translation intended to cooperate with the LP turbine shaft. These means 58 here comprise a radially outer annular flange whose outer periphery is crenelated and defined claw teeth axially engaged in a toothing complementary shape of a downstream end of the LP turbine shaft. A nut 60 and a locking ring 62 can be mounted on this end of the LP turbine shaft to complete the assembly and prevent unintentional disassembly of the section 20c.

The turbine shaft 4 comprises, substantially around the sealing means 40, an annular row of axial orifices 63 of air passage, from the downstream to the upstream, to feed a first annular cavity L1 delimited on the one hand by the tube 20 and on the other by the shafts 4, 8. The air contained in this cavity L1 then passes through the orifices 32 and enters an annular pressurizing cavity L2. The sealing means 22 are here located between the cavity L2 and the lubrication chamber E1 and the sealing means 31 are located between the cavity L2 and the cavity R of the de-oiler. The cavity L2 here extends around the wall 25.

The operation of the degassing tube 20 according to the invention will now be described. As mentioned above, de-oiled air enters the cavity R through the de-oiling system of the upstream chamber E1 (arrow 18). This oiled air is accelerated as it approaches the axis of rotation of the turbomachine and is further driven through the filter cartridge 30 (arrow 70). The filter of the cartridge retains the oil drops which are centrifuged and radially outwardly passed through the perforations of the envelope and projected onto the radially inner surface of the upstream section 20a (arrow 71). .

The calibration of the oiled air flow is done upstream in the free vortex part of the deoiling system, in particular by the sealing gaps. The filter cartridge 30 serves to trap the additional oil drops, it is preferable to ensure enough section not to do too much pressure drop while keeping filter mesh fine enough to capture as much oil as possible

This type of filter is new in a turbomachine, it is preferably composed of a calibrated developed mesh or a multi-perforated sheet calibrated fairly thin in any conventional metallic material with a temperature up to 200 ° C to provide a strong surface and most of the drops of oil passing through it stick to it and are then centrifuged on the upstream section 20a where the fitted slope allows the oil to return upstream and into the enclosure E1 (arrows 71, 19). The definition of the mesh is for example between 5 and 25 microns.

Through the filter, the oiled air arrives in the middle. The right path being plugged by the dome 30c envelope, it is forced to cross the rotating walls of the filter. The drops of oil, because of their viscosity will stick to the filter (kind of roasting).

The air will continue its way along the tube after bypassing this obstacle. The grid will load more and more oil. As it turns, as soon as the amount of oil is sufficient it will be centrifuged against the upstream section 20a. The latter also rotates and the fitted slope allows the oil to return to the cavity R by passing through the orifices 38 of the flange of the filter cartridge 30, then to the enclosure E1 (arrows 71, 19).

The air passing through the filter is also radially outwardly into the space 38 where it is then conveyed downstream to the downstream end of the cartridge 30 and then through the pipe sections 20b and 20c. until it is ejected to the atmosphere at the downstream end of the turbomachine.

Claims (10)

1. Degassing tube (20) for a geared-up aircraft turbine engine, the degassing tube having an elongated shape and being adapted to extend at least partly along and inside a turbine shaft ( 4) of the turbomachine, characterized in that it comprises at least one upstream section (20a) comprising on the one hand peripheral means (28) for securing in rotation with an input shaft (8) of a gearbox ( 7) and first peripheral sealing means (26) configured to cooperate with said input shaft. 2. Tube (20) according to the preceding claim, wherein it further comprises second peripheral sealing means (22) configured to cooperate with a fan shaft (3) intended to be driven by said gear. The tube (20) according to claim 1 or 2, wherein said upstream section (20a) comprises an upstream portion (20aa) of larger diameter, an intermediate portion (20ab) of intermediate diameter and a downstream portion (20ac) of smaller diameter, the upstream and intermediate portions being interconnected by a first frustoconical wall and the intermediate and downstream portions being interconnected by a second frustoconical wall. 4. Tube (20) according to the preceding claim, wherein said second sealing means (22) are located on the upstream portion (20aa), and said first sealing means (26) and securing (28) are located on said intermediate portion (20ab). 5. A turbomachine (1) for a geared aircraft, comprising at least one turbine shaft (4) whose upstream end is fixed to an input shaft (8) of a gearbox (7), and a fan (S ) of which a shaft (3) is fixed to an output shaft (9) of the gearbox, fifth sealing means (31) being mounted between the input shaft of the gearbox and the fan shaft or the shaft output of the gearbox, characterized in that it comprises a tube (20) according to one of the preceding claims. 6. A turbomachine according to claim 5, wherein said second peripheral sealing means (22) are located between an annular pressurization cavity (L2) and a cavity (R) of a de-oiling system, and said fifth peripheral means of sealing (31) are located between said annular pressurizing cavity and a lubrication chamber (E1). 7. A turbomachine according to the preceding claim, wherein said pressurizing cavity (L2) is in fluid communication through air calibration holes (32) through an outer annular ring (29) for supporting said first peripheral sealing means ( 26), with another annular cavity (L1) extending around said upstream section (20a). 8. Turbomachine according to the preceding claim, wherein said other pressurizing cavity (L1) is configured to be supplied with compressed air taken from a compressor of the turbomachine. 9. A turbomachine according to one of claims 6 to 8, wherein said deoiling cavity (R) communicates with said lubrication chamber (E1) by an annular row of deoiling tubes (21) which pass radially through said fan shaft ( 3). 10. The turbomachine according to one of claims 6 to 9, wherein said lubrication chamber (E1) contains said gear (7) and bearings (10, 13, 14).